fixed_sized_memory_block_allocator.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2021 John Wellbelove
 
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#ifndef ETL_FIXED_MEMORY_BLOCK_POOL_INCLUDED
#define ETL_FIXED_MEMORY_BLOCK_POOL_INCLUDED
 
#include "platform.h"
#include "alignment.h"
#include "generic_pool.h"
#include "imemory_block_allocator.h"
 
namespace etl
{
  //*************************************************************************
  //*************************************************************************
  template <size_t VBlock_Size, size_t VAlignment, size_t VSize>
  class fixed_sized_memory_block_allocator : public imemory_block_allocator
  {
  public:
 
    static ETL_CONSTANT size_t Block_Size = VBlock_Size;
    static ETL_CONSTANT size_t Alignment  = VAlignment;
    static ETL_CONSTANT size_t Size       = VSize;
 
    //*************************************************************************
    //*************************************************************************
    fixed_sized_memory_block_allocator() {}
 
  protected:
 
    //*************************************************************************
    //*************************************************************************
    virtual void* allocate_block(size_t required_size, size_t required_alignment) ETL_OVERRIDE
    {
      if ((required_alignment <= Alignment) && (required_size <= Block_Size) && !pool.full())
      {
        return pool.template allocate<block>();
      }
      else
      {
        return ETL_NULLPTR;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    virtual bool release_block(const void* const pblock) ETL_OVERRIDE
    {
      if (pool.is_in_pool(pblock))
      {
        pool.release(static_cast<const block* const>(pblock));
        return true;
      }
      else
      {
        return false;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    virtual bool is_owner_of_block(const void* const pblock) const ETL_OVERRIDE
    {
      return pool.is_in_pool(pblock);
    }
 
  private:

    struct block
    {
      char data[Block_Size];
    };

    etl::generic_pool<Block_Size, Alignment, Size> pool;
  };
 
  template <size_t VBlock_Size, size_t VAlignment, size_t VSize>
  ETL_CONSTANT size_t fixed_sized_memory_block_allocator<VBlock_Size, VAlignment, VSize>::Block_Size;
 
  template <size_t VBlock_Size, size_t VAlignment, size_t VSize>
  ETL_CONSTANT size_t fixed_sized_memory_block_allocator<VBlock_Size, VAlignment, VSize>::Alignment;
 
  template <size_t VBlock_Size, size_t VAlignment, size_t VSize>
  ETL_CONSTANT size_t fixed_sized_memory_block_allocator<VBlock_Size, VAlignment, VSize>::Size;
} // namespace etl
 
#endif